An audio/video information system for recording and playing back audio/video information has been described in U.S. Pat. Nos. 3,909,517; 3,842,194 and 3,842,217 to Clemens, herein incorporated by reference. According to this system, audio/video information is recorded in the form of geometric variations in a spiral groove on the surface of a disc. Disc replicas are then made of an insulating material such as vinyl and are coated, first with a conductive material, and then with a dielectric film. A metallized stylus is utilized as a second electrode forming a capacitor with the video disc. The audio/video information is monitored by the stylus which notes changes in capacitance between the stylus and the video disc as the geometric variations in the form of depressions pass under the stylus. The groove density of the video disc is generally from about 1000 to 10,000 grooves per inch (400 -4,000 grooves per cm).
In one embodiment of this system, a polymeric dielectric layer is formed from styrene monomer which is deposited in a glow discharge, as described in U.S. Pat. No. 3,843,399 to Kaplan et al. While this dielectric coating is operative, it has been sought to improve the bonding between the polymeric dielectric layer and the conductive layer. In U.S. Pat. No. 3,982,066 to Nyman et al and in U.S. Pat. Nos. 3,984,907 and 4,004,080 to Vossen, Jr. et al, herein incorporated by reference, the adhesion of the polymeric dielectric layer to a conductive layer is improved by utilizing copper in the conductive layer at the dielectric interface. The copper is either employed as a separate layer interposed between a nickel/chromium/iron alloy layer and the polymeric layer or the copper is used to form a pseudo alloy with the nickel/chromium/iron alloy. While the copper improves adhesion it also increases the chance of degradation and instability.